Cut pile fabrics have a variety of applications for which they are particularly suitable. As used herein, the term "cut pile fabric" refers to a fabric which comprises a ground fabric into which are positioned upwardly facing cut pile tufts. A number of methods for producing such fabrics are well known and include cutting loop pile tufts to thereby produce cut pile or by plush weaving techniques wherein upper and lower ground fabrics are woven and are interconnected by pile yarns extending therebetween. By cutting the pile yarns between the two fabrics, a resulting cut pile face can be produced on each fabric.
One recent relatively widespread use of cut pile fabrics has been in the manufacture of automotive upholsteries. In such applications, these fabrics are especially useful for seating surfaces as they are more comfortable to the touch in both hot and cold weather and have a rich appearance, feel and texture. Accordingly, improved production of such fabrics is currently commercially significant.
One recently developed method of forming cut pile fabrics suitable for the facing portions of automotive upholstery includes the use of "wrap yarns". As the name implies, a wrap yarn is formed by wrapping a binder strand, usually made up of one or more continuous synthetic filaments, around an untwisted body strand produced from staple fibers. Because the binder strand imparts structural integrity to the entire wrap yarn, no twist is necessary in the body strand. When used to form the upstanding pile portions of a cut pile fabric, wrap yarns provide good surface coverage and appearance. The untwisted characteristics of the body strands allows the cut faces of the staple fibers to blossom or spread apart to a greater degree and enhance their surface coverage.
Nevertheless, although suitable for certain upholstery applications, cut pile fabrics made from such wrap yarns also suffer from particular disadvantages characteristic of their nature and construction. One serious problem arises from the differences between the fiber characteristics of the body strand and those of the binder strand. As stated earlier, the body strand is formed from staple fibers of particular individual or blended character and the binder strand is typically formed of continuous filaments of a different fiber having a different character. Accordingly, obtaining a consistent, identical color for the binder and body strands is almost impossible even where the wrap yarn or fabric made from it is piece dyed. When such yarns are dark colored yarns, the visible difference in color between the binder strands and the body strands is increasingly troublesome, even though the binder strand typically makes up less than 10 percent of the total weight of the wrap yarn. The result can be described in textile jargon as a "salt and pepper" effect in which the differently colored or non-colored binder yarns appear on the face of the cut pile fabric. To date, however, no satisfactory solutions have existed for obtaining the desired coverage and texture of cut pile fabrics formed from wrap yarns while avoiding the accompanying aesthetic problems.
One attempt at eliminating the aesthetic problems associated with cut pile fabrics formed from such wrap yarns has been to include a flat monofilament binder strand as part of the wrap yarn. Generally speaking, such flat monofilament fibers are most often colorless and transparent and consequently are not visible on the face of a cut pile fabric the way less transparent textured multifilament binder strands are. Typical commercial multifilament strands often appear white. Nevertheless, because a single flat monofilament binder strand will of necessity usually be larger than would be the individual filaments of a multifilament binder strand, the relatively large and consequently stiffer binder yarn gives the resulting pile fabric a poor hand which is bristly or prickly to the touch.
A second problem characteristic of such fabrics is that the low twist characteristics of the body strand which are so favorable in the final product can cause handling problems during the process or finishing steps in forming the fabric. In particular, because the staple fibers of the body strand essentially have no twist, they are characteristically held together by binder strands which, as stated above, are typically present less than 10 percent by weight. As a result, the body strand tufts of the wrap yarns tend to become detached from the ground yarns of the fabric when the wrap yarns are cut to form the piles of a fabric. The result is a troublesome loss of the cut pile tufts. If enough of the pile tufts become dislodged from the fabric, the resulting deterioration of the integrity and appearance of the fabric can relegate the fabric to second quality.
Accordingly, there exists the need for enhancing the structural integrity of such fabrics during their manufacture as well as improving the appearance of the resulting fabrics.
It is thus an object of the present invention to provide a cut pile fabric formed from wrap yarns which includes the desired surface characteristic wrap yarns provide, but which overcomes the problems attendant to stiff and/or visible binder strands by use of shrinkable low-melt binder strands.
It is a further object of this invention to provide a cut pile fabric in which the low-melt binder strands are shrunken or retracted inwardly from the face of the cut pile fabric so as to be hidden among the cut pile tufts and not visible on the face of the fabric.
It is a further object of this invention to provide a wrap yarn formed from a body strand and a low-melt binder strand of such characteristics that when included in a cut pile fabric, the binder strands will retract away from the face of the cut pile fabric and be hidden among the pile tufts and not visible on the face of the fabric.
It is another object of the invention to provide a cut pile fabric from a wrap yarn which is formed of a shrinkable, low-melt fusible material so that the fabric can be treated to fuse the binder strands and thereby connect binder strands, body strands and ground yarns to one another and enhance the integrity of the fabric.
It is yet another object of the invention to provide a method of making a cut pile fabric having enhanced surface characteristics and a consistent aesthetic appearance by forming a pile fabric from wrap yarns in which the binder strand is formed of a shrinkable low temperature fusible thermoplastic polymer material and helically wrapped around the body strand, so that when the pile tufts formed from such yarns are cut to form the cut pile fabric face and the fabric heat treated in a finishing process, the shrinking and fusion of the binder strand draws it inwardly from the face of the fabric, keeps it hidden among the pile tufts and causes it to interconnect the staple fibers of the body strand and interengaging ground yarns of the resulting fabric.
It is a further object of the present invention to use the regular aspects of fabric finishing treatment to enhance the retraction and effect fusion of such binder strands inwardly away from the face of the cut pile fabric.